1. Field of the Invention
The present invention relates to a wireless communication system, and a wireless communication method in the wireless communication system.
2. Description of the Related Art
Awareness of crime prevention has improved year by year. In recent years, a demand for the realization of entrance monitors or the like through simple installation at a low cost even in single occupant households such as detached houses as well as studio apartments is increasing.
According to such a demand for the simple installation at a low cost, an entrance monitor in which a slave device of the entrance monitor or a master device of the entrance monitor is driven by a battery, and both of the devices are caused to perform wireless communication, making wiring work unnecessary, has begun to spread. In this case, since work for battery replacement occurs when the battery lifetime of the battery mounted on the slave device or the monitor master device expires, there is a need for a wireless communication system for reducing power consumption.
As a method of implementing reduction of power consumption of such a wireless communication system, a wireless communication technology in which a called station repeats regular reception, and a calling station continuously transmits a capture signal longer than an interval of the regular reception of the called station to transition to a constant operation, disclosed in, for example, Japanese Patent Unexamined Publication No. 2003-087180, is known.
Further, technology of a wireless master device (calling device) for suppressing useless continuous transmission when a call signal is continuously transmitted to an intermittently receiving wireless slave device (locator) so as to establish synchronization of transmission and reception, disclosed in, for example, Japanese Patent Unexamined Publication No 2014-082615, is known.
However, although the technology disclosed in Japanese Patent Unexamined Publication No. JP 2003-087180 can achieve a certain object of reducing power consumption of the called station (slave device), reduction of power consumption on the master side has not been considered. Further, the technology disclosed in Japanese Patent Unexamined Publication No. 2014-082615 is intended to reduce the power consumption for a transmission operation on the master side, in addition to reduction of the power consumption of the wireless slave device (locator), but reduction of power consumption of operations, including a reception operation, has not been considered.